Analysis On The Thermal Economy In Circulation Fluidized Bed Thermal Power Unit

Recently,in the process of energy production and utilization,China's environmental and resource problems more and more important,and the energy conservation and emissions reduction of thermal power generation is paid much more attention.With Circulating Fluidized Bed power units becoming larger capacity,higher parameter and more adapted to the inferior coal,some thermal economic problems arise.Therefore,it is necessary to apply quantitative analysis to the thermal system of CFB unit,in order to save energy and exploit the thermal economy potentialities of the unit.This paper build the structure of main and auxiliary system,with classifying the auxiliary system and attaching the auxiliary system to the main system.According to the expression of cycle efficiency,the energy efficiency distribution matrix equation is derived.The practical example is used to verify the method of energy efficiency distribution matrix,and the general steps for programming are listed in this paper.Besides,in the view of the fifth auxiliary flow,the concept of the auxiliary flow is expanded.Then the generalized form of energy efficiency distribution matrix equation is given,in order to prepare for the further discussion of boiler related auxiliary flow`s influence on the cycle efficiency.From three respects of auxiliary flow,known as the regenerative system,turbine auxiliary flow system and boiler auxiliary system these,the variable factors affecting the thermal efficiency is analyzed respectively.According to local influence system of energy balance and mass balance,the changes of each element of the matrix equation is discussed and listed.In addition,the influence degree of the change tendency of the cycle efficiency is analyzed.By applying the concept of the fifth auxiliary flow,the boiler related auxiliary flow`s influence on the cycle efficiency is considered to be the combination of one or several auxiliary flows,and the boiler related influential factors,such as boiler blow-off,steam cooling spray and waste heat utilization,are quantitatively analyzed.The practical example of CFB unit is discussed by processing the parameters,calculating the thermal efficiency and analyze the influence of local thermal economic changes.By using the local influence factors analysis of energy efficiency matrix method,this paper gives quantitative analysis of the influential factor,such as terminal difference of the heaters,extraction steam pressure loss,heat loss,insufficient of drained water cooling,the shaft seal leakage of steam turbine,desuperheating water spray and reheater spray,and the change trend of different factors are compared.According to the trend determine the part and the corresponding parameters which are more influential on the cycle efficiency,so as to monitor and avoid the thermal efficiency loss.Moreover,the increase of cycle efficiency of ash cooler is calculated.Finally,different connection schemes of CFB ash-cooling condensed water are compared on the basis of the increase of energy efficiency,and one scheme is put forward as an optimized scheme.